1. Field of the Invention
The present invention relates to an adhesive composition, an adhesive composition for circuit connection, a connected body and a semiconductor device.
2. Related Background of the Invention
In a semiconductor element and a liquid crystal display element, various adhesives are used for the purpose of bonding various members in the elements. Such adhesives require a wide variety of properties such as adhesiveness, heat resistance and reliability in a state of high temperature and high humidity. Various base materials, an organic base material such as a printed wiring board and a polyimide, a metal such as copper and aluminum, ITO (Indium tin oxide), SiN, SiO2 and the like, are used as an adherend for adhesion. These base materials have a wide variety of surface conditions. Therefore a molecular design adjusted to each adherend is necessary.
Conventionally, there has been used a thermosetting resin using an epoxy resin exhibiting high adhesiveness and high reliability as an adhesive for the semiconductor element or a liquid crystal display element (for instance, Japanese Patent Laid-Open Publication No. 1-113480). As the constituent components of the resin, an epoxy resin, a curing agent such as a phenol resin having reactivity with the epoxy resin, and a thermally latent catalyst to enhance a reaction between the epoxy resin and the curing agent are generally used. The thermally latent catalyst is an important factor to determine a curing temperature and a cure rate. Thus, various compounds have been used from the viewpoint of storage stability at room temperature (25° C.) and a cure rate on heating. In an actual process, desired adhesion properties are obtained by curing at a temperature of 170 to 250° C. for 1 to 3 hours. However, due to the recent higher integration of semiconductor elements and higher definition of liquid crystal elements, a pitch between elements and a pitch between wires have been narrower, and thus there is a possibility of adversely affecting the peripheral members due to the heating at the time of curing. In order to achieve a further lower cost, the throughput needs to be improved. Thus adhesion at a low temperature (100 to 170° C.) in a short time (within an hour), that is, adhesion in a low temperature rapid curing is required. In order to achieve the low temperature rapid curing, it is necessary to use a thermally latent catalyst of a low activation energy, however it is known that it is extremely difficult for such thermally latent catalyst to have storage stability around at room temperature at the same time.
Recently, a radical curable adhesive in which a (meth) acrylate derivative, and peroxide as a radical initiator are used together has attracted attention. Since a radical as reaction active species is extremely highly reactive, curing in a short time is possible by radical curing. And a radical initiator exists stable below a temperature of decomposition thereof. Therefore radical curing is a curing system combining a low temperature rapid curing and storage stability around at room temperature (for instance, Japanese Patent Laid-Open Publication No. 2002-203427).